Prospective evaluation of thin-layer agar colour test in routine diagnosis of multidrug-resistant TB

Int J Tuberc Lung Dis. 2024 Aug 1;28(8):387-394. doi: 10.5588/ijtld.23.0536.

Abstract

<sec><title>BACKGROUND</title>This study evaluated the diagnostic performance of the thin-layer agar MDR/XDR-TB Colour Test (CT), a Mycobacterium tuberculosis complex (MTBC) detection and direct drug susceptibility testing (DST) method with routine sputum, bronchoalveolar lavage and pleural fluid specimen.</sec><sec><title>METHODS</title>In a prospective study, the time and rate of MTBC detection were compared between CT, Löwenstein-Jensen, and MGIT media. Times until DST result, sensitivities, and specificities were evaluated between CT and MGIT 960 indirect DST.</sec><sec><title>RESULTS</title>The cultivation of 177 pulmonary specimens resulted in 83 MTBC-positive cultures. The sensitivity of CT for MTBC detection was 81.3% with a median time of 20 days compared to 13 days and 93.5% for MGIT. The sensitivity of CT for DST results was 100% for isoniazid and levofloxacin and 94.7% for rifampicin. The specificities for isoniazid and rifampicin DST were 97.3% and 98.0% for levofloxacin. The median time until a DST result was significantly shorter with CT than the BACTEC MGIT 960 system, 20 and 27 days, respectively, independent of the specimen type used.</sec><sec><title>CONCLUSIONS</title>The CT is a highly accurate and fast initial diagnostic test for high-incidence settings and could also be used as a first culture and direct DST in peripheral settings.</sec>.

Publication types

  • Comparative Study
  • Evaluation Study

MeSH terms

  • Adult
  • Agar
  • Antitubercular Agents* / pharmacology
  • Bronchoalveolar Lavage Fluid / microbiology
  • Culture Media
  • Female
  • Humans
  • Male
  • Microbial Sensitivity Tests*
  • Middle Aged
  • Mycobacterium tuberculosis* / drug effects
  • Mycobacterium tuberculosis* / isolation & purification
  • Pleural Effusion / diagnosis
  • Pleural Effusion / microbiology
  • Prospective Studies
  • Sensitivity and Specificity*
  • Sputum* / microbiology
  • Time Factors
  • Tuberculosis, Multidrug-Resistant* / diagnosis
  • Tuberculosis, Multidrug-Resistant* / drug therapy

Substances

  • Antitubercular Agents
  • Agar
  • Culture Media